1. Field of the Invention
The present invention relates to a ballpoint pen, and more particularly, to a ballpoint pen with a ball bearing of a shape memory alloy (SMA).
2. Description of the Related Art
Ballpoint pens with oily, aqueous or intermediate inks are the most popular writing implements in the world. However, when a ballpoint pen is carelessly dropped, suffers impact at the point, or excessive force is applied, problems of ink leaking or failing to flow are likely to occur, despite ink remaining in the reservoir. An abraded or deformed ball bearing cannot successfully rotate at the pen point, limiting the space for flowing ink. Writing performance is compromised including uneven flow of ink, uncomfortable writing, increased flow of ink, or a failure to even write. Furthermore, in the fabrication of the ballpoint pen, the existence of deformation, stress and abrasion on the interior of the point assembly influences the writing performance.
Since the conventional ballpoint pen is easily deformed even with careful operation, it normally has a short lifetime, that is, the user needs to renew the point assembly or buy a new pen in a short time even when the reservoir is filled with ink. This is inconvenient and costly for users. In addition, with regard to environmental awareness, excessive ink remaining in the non-functional pen creates a resource waste and environmental pollution. Therefore, to increase the efficiency of the ballpoint pens, developments of a ball bearing able to overcome these problems is called for.
The present invention provides a ballpoint pen with a ball bearing of a shape memory alloy (SMA) to solve the problem of ink failing to flow when the ballpoint pen is dropped on the ground.
The ballpoint pen has an ink reservoir tube storing ink, a point assembly disposed at one end of the ink reservoir tube, and a ball bearing held at the front end of the point assembly. The ball bearing of a shape memory alloy, referred to a SMA ball bearing, is formed of materials selected from a TiNi intermetallic compound or a TiNi based alloy consisting of V, Cr, Mn, Fe, Co, Cu, Hf, Al, Pt, Si, Au, Pd and Zr.
Accordingly, it is a principal object of the invention to provide the SMA ball bearing with pseudoelasticity to prevent deformation from improper use or any other damaging conditions.
Another object of the invention is to increase the friction between the SMA ball bearing and the writing paper.
Yet another object of the invention is to assure the writing performance, such as comfortable writing sensation, normal flow of ink, and a long lifetime.
It is a further object of the invention to provide consistent, dependable ballpoint performance without renewing the point assembly or buying a new pen in a short time.
Still another object of the invention is to decrease the probability of discarding pens with remaining ink.
Another object of the invention is to solve the problems of resource waste and environmental pollution.
It is an object of the invention to achieve the purpose of preventing fatigue from compressive and tensile forces on the SMA ball bearing.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.